The rose diagram shows only the swells directed at Gileston that coincided with light winds or offshore conditions through a typical March. It is based on 2220 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. Green and yellow represent increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In both graphs, the area of any colour is proportional to how frequently that size swell was forecast.

The diagram suggests that the prevailing swell direction, shown by the biggest spokes, was WSW, whereas the the prevailing wind blows from the W. The chart at the bottom shows the same thing but without direction information. For example, swells larger than 1.5 feet (0.5m) coincided with good wind conditions 0.5% of the time, equivalent to 0 days. Open sea swells exceeding >3m (>10ft) are unlikely to occur in a normal March. Taking into account the fraction of these swells that coincided with predicted offshore winds, and given the fact that Gileston is quite sheltered from open water swells, we estimate that clean surf can be found at Gileston about 0.5% of the time and that surf is blown out by onshore wind 16% of the time. This is means that we expect 5 days with waves in a typical March, of which 0 days should be surfable.

IMPORTANT: Beta version feature! Swell heights are open water values from NWW3. There is no attempt to model near-shore effects. Coastal wave heights will generally be less, especially if the break does not have unobstructed exposure to the open ocean.